I climbed Cobb Mtn from Whispering Pines on 12/30/2009. The road near the gate seems to get use from locals, however a little ways up the road becomes covered in pine needles and has many fallen trees across it. Most of the roads on this hike haven't been driven on in years, with the exception of the area near the gate and between the two summits with transmitters at the top. I wouldn't worry too much about avoiding work days--any vehicular traffic at the top would be easily avoided by stepping into the bushes.